To provide a formed filter which is used in a dust collector in an incineration system and has high filtration efficiency while ensuring desired heat resistance.

Filter cloth 10 is composed of a base cloth layer 12 consisting of a woven fabric of an inorganic fiber and a filtration layer 14 which is formed on one side of the base cloth layer 12 and consists of an organic heat-resistant fiber such as a polytetrafluoroethylene (PTFE) fiber and a polyphenylene sulfide (PPS) fiber. At least the filtration layer 14 of the filter cloth 10 is impregnated with a PTFE resin and a polyimide resin. The impregnated PTFE resin and polyimide resin are solidified. The resulting filter cloth is pleated. A quartz-based inorganic hardening agent is applied to a corner part 10A of the pleated filter cloth on the side of the filtration layer and hardened to reinforce the pleated filter cloth.